1. Description of the Related Art
The invention relates generally to shipbuilding, and more particularly to sailing yachts having a centerboard.
2. Background of the Invention
There are known sailing yachts provided with a straight drop-keel or centerboard.
Accommodated in the middle portion of the yacht hull is a rectangular centerboard well receiving a substantially rectangular centerboard capable of movement in the vertical plane. Sliding of the centerboard from the well is prevented by lock pins.
Substantial manual efforts are required for dropping or retracting the centerboard whereas a system of tackles is required in the "Micro" or larger class yachts. The sailing yachts having a drop-keel centerboard are usually so constructed that in the raised position the centerboard occupies much space either in the cockpit or in the cabin. This in turn makes such yachts less comfortable, another disadvantage of such yachts being a rather low sailing performance, due to that the drop-keel centerboards do not allow the yachts to head in the wind accompanied by an increase in the hydraulic resistance and reduction in the speed of the yacht.
There is also known a centerboard sailing yacht as described in U.S. Pat. No. 3,547,065. The straight centerboard is fashioned as a parallelogram with a system for raising and lowering the centerboard including guides inside the centerboard well with rollers on which the centerboard moves.
Modification of the system for raising and lowering the centerboard substantially facilitates handling of the yacht, although fails to make the yacht more comfortable. However, a principle disadvantage of such a yacht is low sailing performance accounted by the shape of the centerboard making it impossible to control the center of sail, and the arrangement of the centerboard relative to the hull. Such structural disadvantages result in an increase in the hydraulic resistance, and consequently in a loss of speed as the yacht heads in the wind.
Attempts to partially obviate the heretofore mentioned disadvantages are known from the same patent U.S. Pat. No. 3,547,065. The sailing yacht described herein comprises a hull the bow part of which accommodates a centerboard well. Provided inside the well are curvilinear guides, and the centerboard moves on rollers. This centerboard easily moves along the guides, whereas its shape and arrangement make the yacht more comfortable by placing the centerboard out of the cabin or cockpit. In addition, the curvilinear shape of the centerboard makes it possible to control the center of lateral resistance of the yacht by changing the position of the geometrical center.
However, while solving partially the known problems, the prototype features such disadvantages as low sailing performance of the yacht. This centerboard construction makes it possible to prevent deviation of the centerboard in the longitudinal centerplane of the yacht which leads, as the yacht heads in the wind, to an increase in the hydraulic resistance and loss of speed. In order to control the center of lateral resistance, the curvilinear guides are such that the height of the centerboard well is greater, affecting the space of the cabin, which makes the cabin less comfortable for the crew. Notwithstanding the fact that such a centerboard construction affords to control the center of lateral resistance, the range of such control is negligeable. Therewith, a change in the lateral resistance of the yacht attainable through retracting the centerboard in the well results in reduced useful surface and consequently in diminishing the principle function thereof, viz., provision of the lateral resistance. It is also to be noted that this construction of the centerboard overcomplicates assembly and repair operations, since the centerboard can be inserted to or removed from the well only through the well outlet at the bottom of the yacht.